Mattress spring core construction over the years has been a continuously improving art with advancements in materials and machine technology. A well known form of spring core construction is known as a Marshall spring construction wherein metal coil springs are encapsulated in individual pockets of fabric and formed as elongate or continuous strings of pocketed coil springs. In an earlier form, these strings of coil springs were manufactured by folding an elongate piece of fabric in half lengthwise to form two plies of fabric and stitching transverse and longitudinal seams to join the plies of fabric to define pockets within which the springs were enveloped.
More recently, improvements in spring core constructions have involved the use of fabrics, which are thermally or ultrasonically weldable to themselves. By using such welding techniques, these fabrics have been advantageously used to create strings of individually pocketed coil springs wherein transverse and longitudinal welds, instead of stitching, are used to form the pockets encapsulating the springs.
Once strings of pocketed springs are constructed, they may be assembled to form a spring core construction for a mattress, cushion or the like by a variety of methods. For example, multiple or continuous strings may be arranged in a row pattern corresponding to the desired size and shape of a mattress or the like, and adjacent rows of strings may be interconnected by a variety of methods. The result is a unitary assembly of pocketed coil springs serving as a complete spring core assembly.
Often a pocketed spring assembly is surrounded with a border made of foam or any other suitable material to provide edge support around the perimeter of the pocketed spring assembly. Such a pocketed spring assembly is mounted upon a base and is completely enclosed within an upholstered covering material. The base and border are known in the industry as a “bucket” into which a pocketed spring assembly may be inserted before the “bucket” is covered with one or more padding or cushioning layers. Upon receiving multiple pocketed spring assemblies, a mattress manufacturer must insert each of the pocketed spring assembly inside a bucket specifically constructed to receive a specified size of pocketed spring assembly. The mattress manufacturer has to construct the foam encasements or “buckets” of different sizes via separate processes, which have proven to be costly due to the labor cost required. Mattress manufacturers would prefer to eliminate the process of building foam encasements or “buckets” and instead receive a pocketed spring assembly within built-in edge support along all four sides of the pocketed spring assembly. It is generally known within the bedding industry that edge supports made of pocketed springs are more durable than foam edge supports.
Therefore, there is a need to provide a pocketed spring assembly having four sides of edge support which may be easily and quickly roll packed for shipping.
There further is a need for a pocketed spring assembly having four sides of edge support without using a bucket, which may be shipped in bulk in a cost effective manner.
There is further a need for a pocketed spring assembly, which when received by a mattress manufacturer, does not require additional edge support to be added, thereby reducing the cost of manufacturing a finished mattress having edge support.